1. Field
Embodiments of the present invention relate to a chainless electric bicycle including a motor to rotate a wheel and a generator connected to a pedal.
2. Description of the Related Art
In general, a chainless electric bicycle comprises a motor to rotate a wheel and a battery to supply power to the motor. Such an electric bicycle can run using rotational force generated from the motor and transmitted to a wheel to rotate the same. The battery is charged by operating a generator connected to a pedal. The operation of the generator is achieved by pedaling.
When riding a bicycle, a rider pedals and rider pedaling force is transmitted to wheels through a chain.
However, a chain has a complicated structure and occupies a large area. In addition, a chain is sometimes disengaged from a wheel, or rider's clothes get caught in a chain or stained.
In order to solve the above problems caused by a chain, chainless electric bicycles have been recently developed and have come onto the market.
In general, chainless electric bicycles can run using rider pedaling force or power of a motor which is operated by pressing a button provided at a handle unit.
A chainless electric bicycle includes a pedal load adjustment unit to adjust a pedal load. Due to the pedal load adjustment unit, when pedaling a chainless electric bicycle, a rider has a “pedal feel” which is similar to what a rider is used to in a typical bicycle having a chain. Accordingly, rider pedaling force is generated when pedaling a chainless electric bicycle.
So as to provide a rider with a “pedal feel” when he/she pedals, a pedal load adjustment unit, which functions as a voltage regulator, adjusts a pedal load applied to pedals by controlling the amount of power generated from a generator by operation of pedals and used to charge a battery.
However, as the amount of power generated from a generator is increased, voltage input to a pedal load adjustment unit rises and heat loss occurs at switching elements and resistors provided in the pedal load adjustment unit. Thus, generating efficiency is decreased and output voltage from the pedal load adjustment unit, which is input to a battery, also rises according to the high input voltage. For this reason, a conventional electric bicycle needs an additional circuit to limit the voltage output from the pedal load adjustment unit.